Without limiting the scope of the invention, its background is described in connection with optical switching.
One example is taught in U.S. Patent Application Publication No. 2004/0227694, filed by Sun and Liu, which discloses a method for a three-dimensional image display using laser induced fluorescence (LIF) of nanoparticles and molecules in a transparent medium. These applicants teach the use of upconversion wherein the stepwise absorbance of two photons from independent laser beams is used to generate a three dimensional image.
Yet another example is found in U.S. Patent Application Publication No. 2015/0029315, filed by Refai, et al., which discloses a system for an ultra high-resolution three-dimensional display. Briefly, an image is generated from two beams of electromagnetic energy. A first wavelength is used to generate an image slice trough a chamber and a second beam is shaped with a line generator across a different axis to generate a three dimensional image.
Yet another example is found in U.S. Pat. Nos. 3,609,706 and 3,609,707, which disclose a photochromic dye based volumetric three-dimensional display that uses 1′,3′,3′-trimethyl-6-nitrospiro(2H-1-benzopyran-2,2′-indoline as a photochromic material.